This research is a biological approach to selective programming and expansion of immunologically naive murine lymphoid cells by incubation with polyadenylic acid containing RNA extracted from specifically sensitized lymphoid cells. The objectives include: (1)\to utilize xenogeneic or allogeneic lymphoid cell-RNA to convert cells to specific antibody production; and then selecting, expanding, and perpetuating these limited numbers of RNA-converted cells by cell fusion with NS-2 or SP2/0 myeloma cells; (2)\to screen by an enzyme-linked immunosorbent assay (ELISA) fused hybrid cells for the production of specific antibodies against RNA-donor immunogens, keyhole limpet hemocyanin (KLH), DNP-oligolysines, or line-10-line-1 tumor antigens; (3)\to clone by limiting dilution techniques, stable, antibody producing RNA-derived hybrids; (4)\to fuse lymphoid cell mixtures from immunosuppressed mice receiving syngeneic cells treated with RNA in vitro and injected in vivo and showing evidence and persistence of specific antibody in the serum; (5)\to assess whether surface idiotypes are present on converted hybrids by anti-idiotypic antibodies and/or antigen binding rosette assays; (6)\to isolate and characterize RNA-derived clonal antibodies and/or surface idiotypes and assess whether they are of murine and/or cavine origin; (7)\to define the technical parameters necessary for successful reproducible RNA-derived cell fusion, and to assess the lymphoid cell surface marker characteristics and numbers of recipient lymphoid cells with these markers; (8)\to extract enriched, homogeneous RNA species from RNA-derived cell clones for serial conversion-cell fusion experiments and further isolation and/or characterizations. The research represents a totally basic and biological approach to several basic questions relevant to the mechanism of RNA conversion of lymphoid cells, and a heretofore untried, innovative approach to the molecular biology of "immune" RNA transfer and antibody formation.